The present invention relates to substrates with fluidic channels and methods for manufacturing.
In some fluid ejection devices, such as printheads, fluid is routed to an ejection chamber through a slot in the substrate. Often, slots are formed in a wafer by wet chemical etching with, for example, alkaline etchants. Such etching techniques result in etch angles that cause a very wide backside slot opening. The wide backside opening limits how small a particular die on the wafer could be and therefore limits the number of die per wafer (the separation ratio). It is desired to maximize the separation ratio.
In one embodiment, a method of manufacturing a fluidic channel through a substrate includes etching an exposed section on a first surface of the substrate, and coating the etched section of the substrate. The etching and the coating are alternatingly repeated until the fluidic channel is formed.